Magnetic resonance imaging is an imaging method in which the spins of atomic nuclei of a subject placed in a magnetostatic field are magnetically excited with radio frequency (RF) pulses with the Larmor frequency of the spins and an image is generated from the data of magnetic resonance signals generated in accordance with the excitation.
In this magnetic resonance imaging, biopsy may be performed. In biopsy, tissue is sampled from a subject and examined, and a puncture needle may be used to sample tissue. For example, when tissue of breast is sampled, in general, the subject is laid facing down on a breast RF coil and a puncture needle is inserted via an instrument that has a grid structure and that is disposed to adhere to a side surface of the breast. For example, a block for fixing the puncture needle is attached to a rectangular hole that is formed by the grid and the puncture needle being fixed by the block is caused to puncture the breast.
In imaging of a breast, it is preferable to dispose coil elements on a side surface of the breast; however, when the number of elements disposed at the side surface of the breast is increased for the purpose of, for example, parallel imaging, the elements partly block the area for puncture so that it is not possible to secure a sufficient puncture area. On the other hand, when elements are disposed around the outer circumference of the whole puncture area to prioritize securing of the puncture area, the diameter of the elements has to be increased, which lowers the performance of parallel imaging in accordance with lowering of the signal noise ratio (SNR) and accordingly extends the imaging time.